1. Field of the Invention
The invention relates to a structure for and method of installation of boring and grooving tools having spring loaded boring and grooving tool drawbars or actuating members therein on machine tool spindles having machine tool hydraulically actuated drawbars or actuating members therein, sensing of broken or worn bits such as grooving bits on the boring and grooving tool, and the guiding and maintaining of concentricity of bits such as grooving bits on the boring and grooving tool.
More specifically, the invention refers to structure for securing a boring and grooving tool having a spring loaded boring and grooving tool actuating member therein to a machine tool spindle having a hydraulically actuated actuating member therein, wherein there is no positive connection between the actuating members so that angular alignment of the boring and grooving tool on the spindle to permit securing of the boring and grooving tool to the spindle is facillitated and the securing of the boring and grooving tool to the spindle is always with the boring and grooving tool flush with the spindle.
The structure of the invention further includes means for measuring escaping air under pressure between the machine tool hydraulically actuated actuating member and an extension of the boring and grooving tool spring loaded actuating member for indicating broken or worn grooving bits on the boring and grooving tool, and means for guiding and maintaining concentricity of the grooving bits in operation of the boring and grooving tool from the outer end of the boring and grooving tool.
The method of the invention includes the securing of the boring and grooving tool flush with the spindle without positive connection between the actuating members. The method of the invention further includes the sensing of air escaping between the extension of the boring and grooving tool spring loaded actuating member and the machine tool hydraulically actuated actuating member to indicate a broken or worn grooving bit and guiding and maintaining concentricity of the grooving bits from the outer end of the boring and grooving tool.
2. Description of the Prior Art
In the past, boring and grooving tools having actuating member therein movable axially within the boring and grooving tool and operable to move cutting tools such as grooving bits radially of the boring and grooving tool in response to such axial movement have been mounted on machine tool spindles having machine tool actuating members extending axially therethrough by first making a threaded connection between the boring and grooving tool actuating member and the machine tool actuating member until the boring and grooving tool body made flush contact with the spindle, at which time the boring and grooving tool was backed off from the spindle sufficient to align bolt openings in the boring and grooving tool body member and spindle. The boring and grooving tool was then secured to the spindle without being exactly flush with the spindle.
With such prior structure, the positive connection between the boring and grooving tool actuating member and the machine tool hydraulically actuated actuating member required exact positioning of the machine tool actuating member during operation so that the grooving bits secured to the boring and grooving tool would be moved radially an exact amount. Such positioning of the machine tool hydraulically actuated actuating member in relation to the boring and grooving tool and grooving bits on the boring and grooving tool required a good deal of time in the past such that boring and grooving tools were not changed except as absolutely necessary and cutting tools such as grooving bits have been adjusted and/or replaced with the boring and grooving tool in assembly on a machine tool spindle. This requires a good deal of downtime for the machine tool during adjusting and replacing of cutting tools as well as promoting the use of cutting tools which are not as sharp as desirable. Furthermore, cutting tools such as grooving bits can be more accurately set in less time off the machine tool to close diameter tolerance so that they will cut to proper size without on the machine adjustments.
Further, in the past there has been no simple method of determining wear of grooving bits on the boring and grooving tool or of sensing a broken grooving bit during operation. Worn grooving bits have in the past generally been determined after gauging of parts produced thereby which particularly in high speed operations may be several parts after the critical wear point has been reached. Further, in the past the positive connection between the machine tool hydraulically actuated actuating member and spring loaded boring and grooving tool actuating member has permitted bending and/or breaking of grooving bits due to excessive hydraulic pressure applied thereto through the machine tool hydraulically actuated actuating member. Bending or breaking of the grooving bits by such excessive pressure again produces undesirable scrap. Also, in the past, wherein boring of openings has been accomplished with triangular boring bit inserts on the end of the boring and grooving tool prior to actuation of grooving bits in the bore cut thereby, the bore is sometines undercut and the grooving bits may not have the required concentricity and may not be properly guided, at least not from the outer end of the boring and grooving tool.